And a lot less population density. People in low-lying areas aren't going to be able to move to higher ground, because someone else already owns that ground.
Why do you say low-lying areas? Do you mean like because of coastal/sea-level rise?
And people think that ground can be owned now
Many animals 'think' it too. Grizzly bears come to mind.
There's a key difference; territorial animals are owner-occupiers. If a bear loses a territorial fight, it dies or moves. It doesn't call in the forest police. Also, bears want to keep other bears out. They don't much care about smaller animals, or try to restructure the entire landscape in the name of bear commerce.